Waste heat recovery system for blow-down water of waste heat boiler

Abstract

The utility model discloses a waste heat recovery system of waste heat boiler blow-down water. The waste heat recovery system comprises a waste heat boiler, a blow-down water pipe, a unit condensate storage tank, a condensate inlet pipe, a heat exchanger, a recovery water pipe, a recovery water tank, a recovery water pump, a condensate delivery pipe and a condensate storage tank. The unit condensate is used for reducing the temperature of waste heat boiler blow-down water and recycling heat, after heat exchange of the heat exchanger, the temperature of the unit condensate rises, the unit condensate can be sent to the deaerator through the condensate tank and pressurized through the pump to serve as waste heat boiler feed water, and the temperature of waste heat boiler blow-down water is reduced, pressurized through the recycling water pump and sent to a circulating water pipe network to be recycled. The field environment around the recycling water tank is obviously improved, meanwhile, the using amount of circulating water and the temperature of circulating return water are reduced, evaporation consumption caused by rising of the temperature of the circulating return water is avoided, meanwhile, the conventional expansion flash evaporation thinking is thoroughly abandoned, and pipeline equipment is prevented from being blocked due to precipitation and scaling of impurities in water.

Description

Technical Field

[0001] The utility model relates to the technical field of waste heat recovery, in particular to a waste heat recovery system for waste heat boiler sewage. Background Art

[0002] A waste heat boiler is a boiler that uses waste heat from the chemical production process to generate steam. Like ordinary power boilers, waste heat boilers are high-temperature and high-pressure equipment that produce power steam. The difference is that the heat source is different. The waste heat boiler uses the waste heat of the process gas in the chemical production process, so it is both a high-energy recovery device and a chemical medium process equipment. Because the feed water entering the waste heat boiler always contains a certain amount of salt, after the waste heat boiler is treated with chemicals, the scaling substances in the boiler water are converted into Water slag In addition, boiler water corrodes metals and also produces some corrosion products. Therefore, there are various soluble and insoluble impurities in the boiler water. During the operation of the waste heat boiler, only a small part of these impurities are taken away by steam, and most of them remain in the boiler water. As the boiler water continues to evaporate, the concentration of these impurities gradually increases, which not only affects the steam quality, but also causes scaling and corrosion of the heating surface, affecting the safe operation of the waste heat boiler.

[0003] In order to control the quality of boiler water, it is necessary to discharge waste heat boiler sewage so as to discharge part of the boiler water contaminated by salt and slag and recycle it into circulating water for use. At present, the waste boiler sewage is directly discharged and recycled, as shown in the figure below. The waste boiler sewage enters the sewage expansion tank, and after being cooled by the circulating water spray at the top of the expansion tank, it enters the recovery water tank and is pressurized by the recovery water pump, and then sent to the circulating water for recycling. Because the temperature of the waste boiler sewage is too high, it is very easy to form scale when using circulating water spray to cool it in the expansion tank, causing nozzle blockage and serious scaling of equipment pipelines. The temperature of the waste boiler sewage cannot be reduced, the on-site discharge volume increases, the water consumption increases, and it is easy to cause damage to the recovery water pump, and it poses a safety hazard to on-site operators.

[0004] Therefore, it is necessary to develop a device that is not easy to scale, can reduce the temperature of waste water from waste heat boilers, recover the heat of waste water, and reduce water consumption. Utility Model Content

[0005] The utility model aims to provide a waste heat recovery system for waste heat boiler sewage, so as to solve the problem of scaling and clogging that is easily formed when spraying in an expansion tank for cooling.

[0006] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0007] A waste heat recovery system for waste heat boiler sewage, the waste heat recovery system comprising:

[0008] Waste heat boilers;

[0009] A sewage pipe, both ends of which are connected to the waste heat boiler and the heat exchanger respectively, and is used to send the sewage from the waste heat boiler to the heat exchanger;

[0010] The unit condensate storage tank is used to store the unit condensate;

[0011] A condensate inlet pipe, the two ends of which are respectively connected to the unit condensate storage tank and the heat exchanger, and are used to deliver the unit condensate into the heat exchanger;

[0012] A heat exchanger, used to utilize the unit condensate from the unit condensate inlet pipe to exchange heat and cool the sewage from the sewage pipe;

[0013] A recovery water pipe, both ends of which are connected to the heat exchanger and the recovery water tank, respectively, for sending the wastewater after heat exchange and cooling to the recovery water tank;

[0014] A recovery water tank, used for receiving the recovery water from the recovery water pipe;

[0015] A recovery water pump, used to pressurize the recovery water in the recovery water tank and send it into the circulating water network for recycling;

[0016] A condensate delivery pipe, both ends of which are connected to the heat exchanger and the condensate storage tank, respectively, for delivering the unit condensate after heat exchange and temperature increase to the condensate storage tank; and

[0017] The condensate storage tank is used to receive the condensate from the condensate delivery pipe as stored water for recycling.

[0018] According to the waste heat recovery system of the present invention, preferably, the waste heat recovery system also includes a deaerator, and the deaerator is respectively connected to the condensate tank and the waste heat boiler, and is used to deoxygenate the water in the condensate tank and use it as feed water for the waste heat boiler.

[0019] According to the waste heat recovery system of the present invention, preferably, the waste heat recovery system also includes a feed water pump, which is arranged between the deaerator and the waste heat boiler, and is used to pressurize the water treated by the deaerator as feed water for the waste heat boiler.

[0020] According to the waste heat recovery system described in the utility model, preferably, the waste heat recovery system also includes a desalted water storage tank and a desalted water inlet pipe, and both ends of the desalted water inlet pipe are respectively connected to the desalted water storage tank and a heat exchanger, which is used to send the desalted water from the desalted water storage tank into the heat exchanger to exchange heat with the wastewater to increase the temperature.

[0021] According to the waste heat recovery system of the present invention, preferably, the heat exchanger is a shell and tube heat exchanger.

[0022] According to the waste heat recovery system of the utility model, preferably, the sewage pipe is connected to the shell side of the heat exchanger, and the condensate inlet pipe and the desalted water inlet pipe are connected to the tube side of the heat exchanger.

[0023] According to the waste heat recovery system of the utility model, preferably, the condensate inlet pipe and the desalted water inlet pipe are respectively provided with a shut-off valve to switch the water source entering the heat exchanger tube.

[0024] According to the waste heat recovery system described in the utility model, preferably, the waste heat boiler includes a furnace body and a furnace tube arranged in the furnace body, wherein the furnace tube is used to transport the heat source, and the furnace body is used to receive boiler feed water to recover the waste heat of the heat source in the furnace tube through heat exchange; the connecting end of the sewage pipe and the waste heat boiler is connected to the furnace body and the furnace tube of the waste heat boiler through a first branch pipe and a second branch pipe respectively.

[0025] According to the waste heat recovery system of the present invention, preferably, the first branch pipe and the second branch pipe are both provided with a manual valve and an automatic control valve.

[0026] According to the waste heat recovery system of the present invention, preferably, the recovery water pump and the feed water pump are both centrifugal pumps.

[0027] Compared with the prior art, the utility model has the following advantages:

[0028] The utility model utilizes the condensate of the unit to reduce the temperature of the waste heat boiler sewage and recover heat. After heat exchange in the heat exchanger, the temperature of the condensate of the unit increases and can be sent to the deaerator through the condensate tank and pressurized by a pump as the waste heat boiler feed water. The temperature of the waste boiler sewage is reduced and is sent to the circulating water network for recycling after being pressurized by the recovery water pump. The on-site environment around the recovery water tank is significantly improved, and at the same time, the circulating water consumption and the circulating return water temperature are reduced, and the evaporation consumption caused by the increase in the circulating return water temperature is avoided. At the same time, the conventional expansion flash evaporation thinking is completely abandoned to avoid the precipitation of impurities in the water and scaling and clogging of pipeline equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic diagram of an implementation of a waste heat recovery system of the utility model;

[0030] Description of reference numerals:

[0031] 1-waste heat boiler; 2-waste water pipe; 3-unit condensate storage tank; 4-condensate inlet pipe; 5-heat exchanger; 6-recovery water pipe; 7-recovery water tank; 8-recovery water pump; 9-condensate delivery pipe; 10-condensate storage tank; 11-deaerator; 12-feed water pump; 13-desalted water storage tank; 14-desalted water inlet pipe; 15-first branch pipe; 16-second branch pipe. DETAILED DESCRIPTION

[0032] In order to enable those skilled in the art to better understand the solution of the utility model, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is only a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the utility model.

[0033] It should be noted that the terms "first", "second", etc. in the specification and claims of the present utility model and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the utility model described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, the process, method, system, product or equipment that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or equipment. In the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other.

[0034] like Figure 1 As shown, in one embodiment, the waste heat recovery system of the utility model includes a waste heat boiler 1, a sewage pipe 2, a unit condensate storage tank 3, a condensate inlet pipe 4, a heat exchanger 5, a recovery water pipe 6, a recovery water tank 7, a recovery water pump 8, a condensate delivery pipe 9 and a condensate storage tank 10; wherein, the waste heat boiler 1 is well known in the art, and includes a furnace body and a furnace tube arranged in the furnace body, wherein the furnace tube is used to transport a heat source, and the furnace body is used to receive boiler feed water to recover the waste heat of the heat source in the furnace tube through heat exchange.

[0035] The two ends of the sewage pipe 2 are respectively connected to the waste heat boiler 1 and the heat exchanger 5, and are used to send the sewage from the waste heat boiler into the heat exchanger; the unit condensate storage tank 3 is used to store the unit condensate; the two ends of the condensate inlet pipe 4 are respectively connected to the unit condensate storage tank and the heat exchanger, and are used to send the unit condensate into the heat exchanger; the heat exchanger 5 is used to use the unit condensate from the unit condensate inlet pipe to perform heat exchange and cooling on the sewage from the sewage pipe; the two ends of the recovery water pipe 6 are respectively connected to the exchanger 1 and the heat exchanger 2; The heat exchanger and the recovery water tank are used to send the wastewater after heat exchange and cooling into the recovery water tank; the recovery water tank 7 is used to receive the recovered water from the recovery water pipe; the recovery water pump 8 is used to pressurize the recovered water in the recovery water tank and send it into the circulating water network for recycling; the two ends of the condensate delivery pipe 9 are respectively connected to the heat exchanger and the condensate storage tank, and are used to send the unit condensate after heat exchange and heating into the condensate storage tank; the condensate storage tank 10 is used to receive the condensate from the condensate delivery pipe as storage water for recycling.

[0036] In a preferred embodiment, the connection ends of the sewage pipe 2 and the waste heat boiler 1 are connected to the furnace body and the furnace tube of the waste heat boiler through a first branch pipe 15 and a second branch pipe 16 respectively, that is, the sewage in the furnace body is sent to the sewage pipe through the first branch pipe, and the sewage in the furnace tube is sent to the sewage pipe through the second branch pipe; preferably, manual valves and automatic valves are provided on the first branch pipe and the second branch pipe to facilitate control and switching.

[0037] In another embodiment, the waste heat recovery system of the utility model includes a waste heat boiler 1, a sewage pipe 2, a unit condensate storage tank 3, a condensate inlet pipe 4, a heat exchanger 5, a recovery water pipe 6, a recovery water tank 7, a recovery water pump 8, a condensate delivery pipe 9, a condensate storage tank 10, a deaerator 11, a feed water pump 12, a desalted water storage tank 13 and a desalted water inlet pipe 14; wherein the two ends of the sewage pipe 2 are respectively connected to the waste heat boiler and the heat exchanger, for sending the sewage of the waste heat boiler into the heat exchanger; the unit condensate The liquid storage tank 3 is used to store the condensate of the unit; the two ends of the condensate inlet pipe 4 are respectively connected to the unit condensate storage tank and the heat exchanger, and are used to send the unit condensate into the heat exchanger; the two ends of the desalted water inlet pipe 14 are respectively connected to the desalted water storage tank 13 and the heat exchanger 5, and are used to send the desalted water from the desalted water storage tank into the heat exchanger to exchange heat with the wastewater and increase the temperature; wherein, the condensate inlet pipe 4 and the desalted water inlet pipe 14 are respectively provided with shut-off valves to switch the water source entering the heat exchanger.

[0038] The heat exchanger 5 is used to use the unit condensate from the unit condensate inlet pipe 4 or the desalted water from the desalted water inlet pipe 14 to perform heat exchange and cooling on the sewage from the sewage pipe 2; the two ends of the recovery water pipe 6 are respectively connected to the heat exchanger and the recovery water tank, and are used to send the sewage after heat exchange and cooling into the recovery water tank; the recovery water tank 7 is used to receive the recovered water from the recovery water pipe; the recovery water pump 8 is used to pressurize the recovered water in the recovery water tank and send it to the circulating water network for recycling; the two ends of the condensate delivery pipe 9 are respectively connected to The heat exchanger and condensate storage tank are used to deliver the unit condensate after heat exchange and temperature increase to the condensate storage tank; the condensate storage tank 10 is used to receive the condensate from the condensate delivery pipe as stored water for recycling; the deaerator 11 is respectively connected to the condensate tank and the waste heat boiler, and is used to deoxygenate the water in the condensate tank and use it as feed water for the waste heat boiler; the feed water pump 12 is arranged between the deaerator and the waste heat boiler, and is used to pressurize the water treated by the deaerator and use it as feed water for the waste heat boiler; wherein the recovery water pump 8 and the feed water pump 12 are both centrifugal pumps.

[0039] In some embodiments, the heat exchanger 5 is a shell and tube heat exchanger, and the sewage pipe 2 is connected to the shell side of the heat exchanger, and the condensate inlet pipe 4 and the desalted water inlet pipe 14 are connected to the tube side of the heat exchanger.

[0040] During operation, the blowdown water in the furnace body and / or furnace tube of the waste heat boiler is sent to the shell side of the heat exchanger through the blowdown water pipe, and the desalted water from the desalted water storage tank or the unit condensate from the unit condensate storage tank is sent to the tube side of the heat exchanger as cold source water through the desalted water inlet pipe or the condensate inlet pipe respectively; in the heat exchanger, the blowdown water exchanges heat with the cold source for cooling; the cooled blowdown water is sent to the recovery water tank through the recovery water pipe as recycled water, and then is pressurized by the recovery water pump and sent to the circulating water network for recycling; the cold source water after heat exchange and temperature increase is sent to the condensate storage tank through the condensate delivery pipe, and then the water stored in the condensate storage tank enters the deaerator for treatment, and the water treated by the deaerator is pressurized by the feed water pump and used as feed water for the waste heat boiler.

[0041] Of course, those skilled in the art will appreciate that the system of the present invention may also be provided with other instruments and / or valves as required, such as online temperature and / or pressure detection instruments, etc. Figure 1 For a clearer and simpler illustration, some devices are omitted in the figure, but this will not affect the understanding of the present invention.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some of the technical features therein by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the various embodiments of the utility model.

Claims

1. A waste heat recovery system for waste heat boiler sewage, characterized in that: The waste heat recovery system comprises: Waste heat boilers; A sewage pipe, both ends of which are connected to the waste heat boiler and the heat exchanger respectively, and is used to send the sewage from the waste heat boiler to the heat exchanger; The unit condensate storage tank is used to store the unit condensate; A condensate inlet pipe, the two ends of which are respectively connected to the unit condensate storage tank and the heat exchanger, and are used to deliver the unit condensate into the heat exchanger; A heat exchanger, used to utilize the unit condensate from the unit condensate inlet pipe to exchange heat and cool the sewage from the sewage pipe; A recovery water pipe, both ends of which are connected to the heat exchanger and the recovery water tank, respectively, for sending the wastewater after heat exchange and cooling to the recovery water tank; A recovery water tank, used for receiving the recovery water from the recovery water pipe; A recovery water pump, used to pressurize the recovery water in the recovery water tank and send it into the circulating water network for recycling; A condensate delivery pipe, both ends of which are connected to the heat exchanger and the condensate storage tank, respectively, for delivering the unit condensate after heat exchange and temperature increase to the condensate storage tank; and The condensate storage tank is used to receive the condensate from the condensate delivery pipe as stored water for recycling.

2. The waste heat recovery system according to claim 1, characterized in that: The waste heat recovery system further comprises a deaerator, which is connected to the condensate storage tank and the waste heat boiler respectively and is used to deoxygenate the water in the condensate storage tank and use it as feed water for the waste heat boiler.

3. The waste heat recovery system according to claim 2, characterized in that: The waste heat recovery system further comprises a feed water pump, which is arranged between the deaerator and the waste heat boiler and is used to pressurize the water treated by the deaerator as feed water for the waste heat boiler.

4. The waste heat recovery system according to claim 3, characterized in that: The waste heat recovery system also includes a desalted water storage tank and a desalted water inlet pipe, the two ends of the desalted water inlet pipe are respectively connected to the desalted water storage tank and a heat exchanger, and is used to send the desalted water from the desalted water storage tank into the heat exchanger to exchange heat with the wastewater to increase the temperature.

5. The waste heat recovery system according to claim 4, characterized in that: The heat exchanger is a shell and tube heat exchanger.

6. The waste heat recovery system according to claim 5, characterized in that: The sewage pipe is connected to the shell side of the heat exchanger, and the condensate inlet pipe and the desalted water inlet pipe are connected to the tube side of the heat exchanger.

7. The waste heat recovery system according to claim 6, characterized in that: The condensate inlet pipe and the desalted water inlet pipe are respectively provided with cut-off valves to switch the water source entering the heat exchanger tube pass.

8. The waste heat recovery system according to claim 7, characterized in that: The waste heat boiler includes a furnace body and furnace tubes arranged in the furnace body, wherein the furnace tubes are used to transport heat sources, and the furnace body is used to receive boiler feed water to recover waste heat from the heat source in the furnace tubes through heat exchange; the connecting ends of the sewage pipe and the waste heat boiler are connected to the furnace body and the furnace tubes of the waste heat boiler through a first branch pipe and a second branch pipe respectively.

9. The waste heat recovery system according to claim 8, characterized in that: The first branch pipe and the second branch pipe are both provided with a manual valve and an automatic control valve.

10. The waste heat recovery system according to claim 9, characterized in that: The water recovery pump and the water supply pump are both centrifugal pumps.

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